The oncogenic potentials of Epstein-Barr virus (EBV) in primates continues to demonstrate presence of EBV genome in epithelial cells in nasopharyngeal carcinoma (NPC), in almost all cases of Burkitt's lymphoma (BL) in Africa but in only a few cases of BL found outside Africa (Europe, U.S.A.), providing strong evidence that this virus is one of major contributing factors in complex etiology of these tumors. Moreover, the oncogenicity of Herpesvirus saimiri (HVS) and Herpesvirus ateles in nonhuman primates and certain rodents relates oncogenic herpesvirus to lymphoproliferative neoplasia. The role of herpesvirus in etiology of certain tumors is further strengthened by isolation and characterization of new classes of herpesvirus from old world monkeys neoplastic and normal tissues. These viruses are B lymphotropic, transforming and share greater than 40% homology with EBV DNA. The International activities consisting of coordination between NCI Viral Oncology Program (VOP), W.H.O. International Reference Program on oncogenic herpesvirus (IRP-OHV), and W.H.O. Program on Comparative Virology were continued. Under this activity, I provided consultation, exchange of scientific data, reference reagents, collection of data on suitable disease models, survey of human subjects working with or associated with oncogenic herpesvirus and input in organization of International Symposium.